In recent years, it has been common to use an electronic throttle control device that detects the actuated amount of a throttle grip or an accelerator pedal and controls, based on the actuated amount of the throttle grip or the accelerator pedal, the opening of a throttle valve through a motor.
When the throttle control device of this type is to be disposed in an engine provided with an injector supplying fuel through injection into an intake passageway, it is desirable that, for example, a motor and a throttle opening sensor be disposed as compactly as possible, while avoiding interference with a fuel injection valve.
An arrangement is known in which the motor is disposed on the same side as the injector. See Japanese Patent Laid-open No. 2002-256895. If the motor is disposed on the same side as the injector, however, a wide space must be provided on an upper portion of the throttle body. This presents the problem of uneven distribution of a space around the throttle body.
In some known configurations, the motor and the throttle opening sensor may be disposed in an axial direction of the throttle valve. This, however, results in the length of the throttle body in the direction of cylinder arrangement being elongated by the length of these parts. This, in turn, leads to an enlarged engine.